1. Field of the Invention
This invention relates to imaging systems for creating a desired pattern on a radiation-sensitive substrate such as those used in microelectronics circuits and boards, and more particularly relates to an energy-recycling imaging system useful as a high-speed precision manufacturing tool for creating a desired pattern, such as via-holes in electronic modules.
2. Description of Related Art
Large-area lithographic exposure systems are required as production tools for the manufacturing of numerous products, including multi-chip modules for high-density electronic packaging, flat-panel displays, printed circuit boards, and semiconductor integrated circuits. Many types of exposure systems are used in the industry, such as contact and proximity tools, projection imaging tools, and direct-write tools. Such systems are often referred to as patterning tools or photolithographic systems.
Of these, the most desirable exposure systems are the projection imaging tools because they provide non-contact imaging, large-area exposure capability, batch processing, and high throughputs. These typically include illumination, imaging, and motion control subsystems. Projection systems employing ultraviolet light sources, particularly excimer lasers, are especially attractive because they enable high-volume, cost-effective production.